Email Marketing Metrics: 9 KPIs for Email Campaigns

What are email marketing metrics?

Email marketing is one of the most prolific digital marketing strategies, not only because it enables you to reach your audience directly, but also because there are so many email marketing metrics (or key-performance-indicators) you can use to improve your campaigns.

These KPIs allow you to analyze the success and impact of your emails and take a data-driven approach to improve them.

So, it’s important to identify these key metrics before you start a campaign. 

What are the primary email metrics?

The best thing about email marketing is the ability to measure the success of each campaign and clearly identify (for the most part) where improvements have to be made.

When you create and launch a campaign with most email service providers, you’ll have access to at least the following metrics:

  • Open rate (OR)
  • Click-through-rate (CTR)
  • Bounce rate
  • Unsubscribe rate

Open rate (OR)

Your open rate is the percentage of recipients who opened your email compared to the total number of sent emails.

Usually, an email open is triggered when an invisible image is loaded in your email. If your recipients don’t have images set to automatically download and they do not enable image loading manually after opening your email, they won’t be counted towards your open rate.

The average open rate for email is between 15%-25%. This can vary based on your industry, but anything at the higher end of this range highlights you’re doing something well.

If a recipient opens your email multiple times, your overall open-rate will be inflated. However, most service providers will also provide you with a Unique Opens metric.

This metric only includes one open from each recipient. If your overall email open rate is far higher than your unique opens, this may show you’ve created a truly special email. As it’s lear people keep coming back to read it.

A poor open-rate might indicate that your subject line isn’t effective enough. Other than the email sender, this will be determine whether or not a recipient opens your email.

A good subject line is personalized and impactful. You can create impact by writing a subject line that targets some emotion in recipients, i.e. anger, interest, curiosity or happiness. Alternatively, you can allude to solving a problem in your subject line.

Let them know you have some information that can address what they need. But don’t give away too much in the subject line, you still want them to open your email.

Click-through rate (CTR)

Your click-through-rate is calculated by the number of clicks in your emails divided by the total number of emails sent.

Naturally, your emails will contain buttons or links to other content you want to share with recipients, whether it’s your product catalogue or a blog post.

Average CTR varies much more wildly based on your industry than open rates, so feel free to refer to this list of email click-through-rates by industry.

How many clicks you receive will depend on the quality of your CTAs, copy and email design. The quality of an email will be subjective to your audience members, so it’s hard to say exactly will improve clicks.

But like we said above, try to solve a problem or fill a gap in knowledge for your audience. This is what readers tend to respond to (and keep coming back for).

For some killer tips on generating clicks, go take a look at our article on writing a call-to-action that converts.

Bounce rate

Your bounce rate is determined by the number of email addresses that returned an error and were unable to be delivered to recipients.

Bounces will fit into one of two categories: hard or soft.

Hard bounces

Hard bounces occur when an email is sent to a non-existent or invalid email address. For example, email addresses that have been closed or those with text errors.

These are categorized as ‘hard bounces’ as the email will never be delivered to those addresses.

Soft bounces

Soft bounces occur when there is an issue that causes deliveries to fail temporarily. For example, their inbox could be full or they may need to whitelist you on their email server (depending on how it was set up). Once the issue has been resolved, your email should be delivered.

Why a low bounce rate is crucial

A high bounce rate means a whole bunch of your emails aren’t getting delivered. Too many bounces occurring continuously can also affect your Sender Reputation with your service provider. This can lead to restrictions being placed on your account. So it’s best to address bounces quickly.

If you do have a large number of bounces, it worth checking if a specific email client is causing this. You don’t want to be in the bad books with Gmail or Live, so if you spot a pattern it’s best to get working on a solution quickly.

Your list health is essential to your campaign success, so remember to clean your email list regularly. You should be removing any emails that result in a hard bounce and also any recipients who never open your emails.

On average, any bounce rate below 2% is no cause for concern, but you should be checking how many of these are hard bounces. If you start seeing bounces rates as high as 5% or 10%, stop sending emails and investigate immediately.

Unsubscribe rate

This is the number of people who have unsubscribed from your email list.

If you start to see an increase in unsubscribes, you need to identify why this is happening. Do unsubscribes occur after a particular email in your chain? Or is it more of a slow burn?

You can change the content in your emails easily enough and even run a few A/B tests to see what results in a decreased unsubscribe rate. Again, you have to continuously provide value to subscribers.

It could also be a result of how frequently you send emails. If you send too many emails in a short time, it can result in fatigue. Try to find that sweet spot with your respondents.

Hey, you can even ask them how often they’d like to hear from you and what other content they’re interested in. Why not create a survey and send it to your audience?

A double-opt-in process for subscriptions can also reduce your unsubscribe rate in the future, as you’ve gone out of your way to ensure your subscribers really want to be on your list.

The average unsubscribe rate is 0.49% according to Smart Insights. But as with all email marketing metrics, this varies based on industry.

Your unsubscribe rate should always be lower than your number of new subscriptions, this is the sign of a healthy subscriber list. We’ll go over how to calculate your list growth rate a bit further down.

Other email marketing KPIs

Whilst we’ve covered the primary email marketing metrics above, they aren’t be be-all and end-all of measuring successing.

Here are some of the other email KPIs you’ll need to track to improve your campaigns:

  • Click-to-open rate (CTOR)
  • List growth rate
  • Opens by device
  • Spam score
  • Conversion rate
  • Return-on-investment (ROI)

Click-to-open rate (CTOR)

The click-to-open rate compares the number of unique clicks to unique opens and therefore is the best way to measure interaction with your emails.

If your CTOR is low, this is likely an indicator that your email design or messaging is off the mark for recipients.

To resonate with readers, your email needs:

  • To be scannable

  • High resolution images

  • Clear, acitonable CTAs

  • Valuable advice or information

Why not perform some split tests with your email content to identify what works best with your audience? Once you have it down, creating future emails will be so much easier.

List growth rate

Your list growth rate is pretty self-explanatory, it’s the rate at which your number of contacts is growing.

You can calculate your growth rate by subtracting your unsubscribes from your number of new subscribers, dividing that by the total number of contacts in your list and multiplying it by 100.

(New Subscribers – Unsubscribes) / Total Number of Contacts * 100 = Growth Rate.

To improve your list growth rate, you have to ask yourself what value you can provide to potential subscribers. We recommend you consider creating a lead magnet, which is a piece of content exchanged for a subscription to your email list. 

Take a look at these 13 lead magnets and how they can be used to grow your email list.

Opens by device

This email metric is pretty straight forward. It highlights what device (desktop, tablet or mobile) your recipients are reading your emails on.

Why is this useful? Well, for example, if most of your recipients are opening on mobile, you can focus on more mobile-friendly designs.

You could also compare opens by device to other email marketing metrics like CTR. If clicks are low on mobile or tablet devices, you may need to see if your design is as responsive as you thought it was.

Spam score

Your spam score is calculated by how many similarities your email has to others that have been blocked by spam filters.

Most spam filters will give you a score between 0-10, but each has a different bar within that range for what they consider spam.

On average, if your score is below 5 then you should be fine. But you need to aim tog et your score as low as possible to ensure you’re below the threshold for all filters.

Take a look at how each spam filter scores emails.

If your provider doesn’t have a spam score calculation built-in, you can always use a free tool like Mail Tester.

Conversion rate

Now, to track your conversion rate, you’ll need to integrate your email marketing software with an external analytics tool (such as Google Analytics).

Your conversion rate should be linked to an action you can clearly track, like a purchase, landing page visit or form submission.

You can then measure how effective your content is in encouraging readers to complete that action. If your conversion rate is low, then you need to do some more testing with new messages and CTAs.

This is an important metric for content marketing, where your whole goal is to get eyes on the content you’ve created. 

Return-on-investment (ROI)

Your ROI is directly linked to the cost-effectiveness of your email marketing campaigns. It is calculated by subtracting the cost of a campaign away from the total revenue made, then dividing that number by the cost of the campaign and multiplying that number by 100.

(Total Revenue Made From Campaign – Total Cost of Campaign) / Total Cost of Campaign * 100 = ROI

To this day, email marketing still has the highest potential ROI of any other type of digital marketing. So, this is an extremely important metric to track and work to improve.

Wrapping up

Email marketing metrics aren’t a one-stop-shop, you have to continuously track their progress from campaign to campaign to identify what you’re doing right and what’s still needs work.

A data-driven approach is the best way to increase engagement with emails and your ROI.

Want to learn more about measuring email campaigns success over time? Head over to our Drip Email Marketing article.